The present invention relates to gas conditioners and is particularly intended for individual protection of man in hazardous environment, e.g. working under the conditions of elevated temperatures, for instance, for creating a microclimate in the under-clothing space of protective clothing.
The present invention can be used to utmost effectiveness by mine workers in deep mines, by operators wearing protective clothing in radioactive and chemically aggressive environments, by foundry workers, by aircraft personnel, etc. The invention is implementable both in a portable device and in a stationary modification, e.g. for installation in driver's or pilot cabs of vehicles and aircraft, in operator's cabs, etc.
There are known gas conditioners intended for protection of human being from thermal action of the environment, by supplying cooled gas under the protective clothing of an operator subjected to an elevated temperature.
A conditioner of this type comprises a source of compressed gas, or else a line for supplying compressed gas to the conditioner, a cooling device and regulating valves and taps for presetting a required temperature duty. Besides, there is incorporated a heat exchanger for precooling the compressed gas fed to the conditioner by means of an individual source of cold.
As the source of cold the aforementioned known conditioners employ a vortex tube of which the action is based on the phenomenon of energy-wise separation of a flow of gas introduced tangentially onto the internal wall of the tube, into two components having the temperatures, respectively, lower and higher than the temperature of the gas being introduced.
However, the hitherto known conditioners of the aforementioned type are not free from disadvantages of which the most serious ones will be discussed hereinbelow.
The vortex tube has been found to perform effectively at a certain speed of the vortex flow; therefore, there is a necessity of incorporating means for stabilizing the pressure of the gas supply. With the flow resistance of the consumer varying, the operating duty of the vortex tube likewise varies, which more often than not affects its efficiency factor.
Adjustment of the characteristics of the microclimate under the protective clothing is complicated at variation of the operating duty of the vortex tube, since at variations of the ratio of the flow rates of the "hot" and "cold" flows their respective temperatures vary, too. Moreover, the efficiency of the operation of the vortex tube is greatly dependent on the geometry, dimensions, shape and surface finish of its main components and of its main flow passage. The sophisticated character of the geometric shapes and the high requirements put before the surface finish raise the cost of manufacture of the gas conditioner, as the whole.
Furthermore, one should not underestimate the fact that in the hitherto known conditioners of the aforementioned type there are no provisions for adjusting the relative humidity, whereas with the gas cooled down to temperatures at which it is fed to the consumer, i.e. to the human being, the relative humidity of the gas may rise to as high as 100%, and droplets may fall out, which either precludes or at least hampers evaporation of sweat and affects the cooling ability of the gas.